One person has been confirmed dead and another 35 people are still missing after an explosion at a Texas fertiliser plant that injured 160, flattened houses and devastated the centre of the town of West.

The missing include five volunteer firefighters from West, four emergency medical service personnel, an off-duty Dallas firefighter and two people from the local community who stopped to help at the scene of a fire at Adair Grain's fertiliser plant before it exploded yesterday with the force of a small earthquake, West Mayor Tommy Muska said in an interview.

The remains of the fertiliser plant burn after the explosion. Photo: Reuters

Search-and-rescue crews that combed the ruins of the World Trade Centre after the 2001 attacks have been dispatched to the scene about 130 kilometres south of Dallas, said Waco Police Sergeant William Patrick Swanton at a news conference today.

Advertisement

"A lot of lives have been lost and some of them are firefighters," Lisa Muska, the mayor's wife, said in an interview today. "We all know each other and care about each other deeply."

The last time a US industrial catastrophe killed so many people was April 2010, when 29 coal miners perished in Massey Energy's Upper Big Branch mine. With the demolished fertiliser facility and some of the surrounding rubble yet to be searched, Swanton said the number of deceased may climb, which would make it the deadliest such incident in Texas since the 1947 explosion aboard the SS Grandcamp freighter that killed more than 570.

A damaged car sits idle as smoke rises in the background. Photo: Reuters

Storing tons

Adair Grain's West Fertiliser handled anhydrous ammonia, a volatile combination of nitrogen and hydrogen that North American farmers inject in liquid form into the soil as a crop nutrient. Adair stored as much as 110,000 pounds of the chemical, according to the Texas State Department of Health Services.

State environmental records showed that as of December 31, the plant also held in storage as much as 270 tons of an ammonia derivative known as ammonium nitrate, a solid fertiliser used by Timothy McVeigh to destroy the Alfred P. Murrah Federal Building and kill 168 people in Oklahoma City in 1995. It was also used in the Irish Republican Army's 1996 Canary Wharf attack in London.

Firefighters use torches to search a destroyed apartment complex near the West fertiliser plant. Photo: AP

A 2011 inspection of the plant by the US Pipeline and Hazardous Materials Safety Administration revealed violations of material-handling rules, according to an agency document. The inspector said the company planned to ship anhydrous ammonia in unauthorised cargo tanks, and had failed to develop a security plan for the transportation.

EPA fine

The agency initially proposed a fine of $US10,100. It was reduced to $US5250 last year, which the company paid. The agency said in its final order in the matter that the company had addressed the violations and "no further corrective actions are required".

Explosion at Texan fertiliser plant

The Environmental Protection Agency inspected the West plant's risk-management plan in March 2006 and found a number of deficiencies. The EPA fined the facility $US2300 in August of that year and directed Adair Grain to correct the shortcomings, Alisha Johnson, an agency spokeswoman, said in an email.

Firefighters in West were battling a blaze at the plant and evacuating nearby residents when it exploded about 7.53pm local time yesterday. A nursing home, hospital and two schools sit less than a mile from the facility on the northeast edge of town. Waco, the seat of McClennan County, is about 33 kilometres south of West.

"I never thought of anything like that happening," said Jenene Picha, manager of the Czech-American Restaurant. Firefighters showed great courage in battling the blaze, she said, and "they knew it was very dangerous out there".

Swanton said the damage to houses ranged "from broken windows to complete devastation". A house-to-house search was in progress. A 50-unit apartment complex suffered severe damage, with the interiors of some apartments visible from the street.

"There are homes that are no longer homes," Swanton said today. "There are homes that have been completely flattened."

In this Instagram photo provided by Andy Bartee, a plume of smoke can be seen rising from the Texas fertiliser plant. Photo: AP

While the site is being treated as a crime scene, there are no indications that the fire was intentionally set, Swanton said. A pair of urban search-and-rescue experts known as Texas Task Forces 1 and 2 has been deployed, as has a Bureau of Alcohol, Tobacco, Firearms and Explosives team of forensic chemists and explosive specialists. The federal agents will be responsible for determining whether the explosion was accidental or criminal, according to a federal official.

Investigation team

The US Chemical Safety Board, which investigates industrial chemical accidents, said on its website that a "large investigation team" should arrive in West today. Amy Vaughan, a geophysicist at the US Geological Survey, said a magnitude 2.1-degree seismic event had been registered as the explosion occurred. The impact would have generated a shock wave, she said by phone from Golden, Colorado.

The worst-hit areas appeared to be the nursing home and apartment building, Swanton said at an earlier briefing. Local television station KWTX showed fires in the ruined plant and in surrounding buildings, and people being treated on a flood-lit sports field.

Trooper DL Wilson, a spokesman for the Texas Department of Public Safety, likened the scene at West to the Iraq war and said the apartment complex now resembled a "skeleton". A nearby school also was badly damaged, and 133 residents of the West Rest Haven Nursing Home were evacuated, some in wheelchairs.

Elderly victims

Wesley Adcock, 29, was delivering a load of concrete to a construction site when he saw a mushroom cloud in his rear-view mirror. He volunteered to ferry victims to hospitals in Waco. The three people he helped were all residents of the nursing home.

"The last lady was 95," Adcock said. "She said she was buried in the bathroom when the ceiling collapsed on her."

In Waco, 28 people were admitted to Hillcrest Baptist Medical Centre, chief executive Officer Glenn Robinson said. Five were in the intensive care unit, two of them in critical condition, he said.

"We're seeing a lot of lacerations, some puncture wounds," Robinson said. Some patients had broken legs and hips and a handful had head injuries. Nine people with burns were transferred to Parkland hospital in Dallas.

The Texas Secretary of State listed Donald R Adair and Wanda L Adair as owners and co-directors of Adair Grain, with Donald serving as president and Wanda as vice president. A man who answered a reporter's telephone call to the company declined to identify himself or comment.

'Terrible smell'

Elizabeth Marquez-Perea, who lives about 1.5 kms north of the plant, said about 50 families lived at Tucker Apartments, the damaged block close to the facility. She and her three daughters fled after the blast shattered windows of their apartment. "It smelled like gas, a real terrible smell," she said.

About a month ago, the school close to the plant had sent parents a note explaining that children had been moved for the day to a different location because of smells coming from the fertiliser plant, Marquez-Perea said.

Crystal Webb said she was preparing to drive her seven-year-old son from her home near the plant to her mother's place in another part of town when the explosion hit.

"It's an indescribable sound and feeling," Webb said. "Every window in my home, every door in my home is completely busted."

The blast tore bricks off the outside of her house, Webb said. She and her son were uninjured.

French blast

"I'm anxious to get home," she said. She didn't know if her house survived the fire.

The disaster was reminiscent of a 2001 fertiliser-factory explosion in Toulouse, France, that killed at least 30, injured more than 2000 and caused more than $US3 billion in property damage. The plant, owned by a subsidiary of oil producer Total SA, wasn't rebuilt. Two years after the incident, French authorities imposed stricter regulations for ammonia production.

The US Federal Aviation Administration issued a temporary flight restriction over West, Janet Napolitano, Secretary of the US Department of Homeland Security, said today before the House Committee on Homeland Security. She said local utilities have turned off service in the area and the Federal Emergency Management Agency has been activated.

"We will continue to monitor events over the course of this day," Napolitano said.

President Barack Obama called Texas Governor Rick Perry from Air Force One while on his way to Boston to offer federal resources that may be needed, said Josh Earnest, a White House spokesman. Obama also told Perry "that his prayers are with the people of West," Earnest said in an email.

Texas Republican Senators John Cornyn and Ted Cruz said in a statement they were "deeply saddened to learn of the horrific explosion in West, Texas".